HPB vs Limestone Screenings: Which is better for under patio stones?

If you are planning a patio or walkway, sooner or later you hit the same fork in the road that trips up a lot of our customers: do you set your stones on HPB or on Limestone Screenings? Both get used under patio stones all the time, both come from crushed limestone, and both look close enough in a bin that it is easy to grab the wrong one. But they behave very differently once your pavers are down and the first winter hits.

At We Deliver Gravel, we handle gravel delivery in Toronto and Vaughan every week and drop off both materials constantly, so let’s walk through how they compare and which one we would put under your patio stones.

Which one wins for patio stones?

For a firm, level bed directly under patio stones and interlock, Limestone Screenings are usually the better choice, because they compact tight and let you screed a clean, flat surface to set your pavers into. HPB is the better pick when drainage matters more, since it is a washed, self-compacting stone that locks up without holding water. Plenty of solid patios use both in layers, which we get into below. Either way, our gravel delivery in Toronto and Vaughan brings the right material straight to your site so you are not hauling it home yourself. The right call really comes down to your soil and how well your yard drains, so let’s look at each material a little closer.

What is HPB?

HPB stands for high performance bedding. It is a small, washed, angular clear stone, usually around a quarter inch, with the fines washed out. The clever part is that even though it has no fines to bind it, its angular shape lets it lock together and self-compact when you tamp it. So you get a firm bed that still drains freely, because water passes through the open spaces between the stones instead of sitting in the layer.

That answers a question we hear a lot, does HPB actually compact? Yes it does. It self-compacts as you tamp it, staying firm while still letting water through, which is why HPB gets used to bed pavers, backfill around pipes, and set under structures where you want support without trapping moisture. Our full breakdown lives in our post on HPB gravel delivery in Toronto.

What are Limestone Screenings?

Limestone Screenings are crushed limestone reduced to roughly quarter-inch chips mixed with fine stone dust. When you dampen and compact them, the dust fills the gaps and the whole layer packs down into a hard, smooth, level surface. That is exactly the bed you want to screed flat and set patio stones into, which is why screenings are the classic setting layer under interlock and flagstone.

People often ask whether Limestone Screenings drain well, and the honest answer is no. All those fines hold moisture, which is exactly why they pack so hard. As a thin setting bed on top of a draining base that is fine, but as a thick base on our heavy clay it can hold water that freezes and shifts your surface. We cover the construction detail in our post on why Limestone Screenings work for construction projects.

HPB vs Limestone Screenings at a glance

Feature	HPB	Limestone Screenings
Made of	Washed 1/4″ clear stone, no fines	1/4″ chips plus stone dust
Compaction	Self-compacting, locks tight	Packs very hard when damp and rolled
Drainage	Excellent, water flows through	Poor, holds moisture
Surface for screeding	Firm but coarser	Very smooth and level
Best role	Free-draining bed and backfill	Setting bed directly under stones
Weakness	Coarser to fine-level	Traps water, can heave on clay

So which goes under your patio stones?

Here is how we usually break it down when a customer calls.

Choose Limestone Screenings if your yard drains well: they are the easier material to screed dead flat, and pavers seat beautifully on them. This is the traditional choice and it works great when the base beneath is solid and water is not pooling.

Choose HPB if drainage is a concern: and on a lot of Toronto and Vaughan lots with clay soil it is. HPB gives you a firm bed that will not trap water against the underside of your patio. Less trapped water means less freeze-thaw movement, which means fewer heaved or wobbly stones a couple of winters down the road. This is also why HPB works so well as a patio setting bed on problem sites, where trapped water would otherwise push your stones around.

Use both in layers for the best of both: a compacted base, then HPB or screenings as the bedding depending on your drainage. On sites where water is a real problem, we often suggest a free-draining stone lower down with the bedding layer on top. If you are also sorting out drainage for a foundation or low spot, our guide on 3/4 clear limestone explains how clear stone handles water.

A few tips before you order

• Get your base right first. Neither HPB nor screenings fixes a soft or poorly prepared sub-base, so excavate to depth and compact before the bedding layer goes down.
• Keep the bedding layer thin. Around an inch of bedding under the stones is plenty. Thick bedding layers are where movement creeps in.
• Match the material to your soil. Clay that holds water leans toward HPB. Well-draining sites can happily use screenings.
• Work out your quantity. For most patios you want about an inch of bedding over your compacted base, and screenings compact down as you roll them, so order a little extra. Our gravel calculator gives you a quick cubic-yard estimate from your measurements, and you can check current rates on our gravel price list.

We deliver HPB and Limestone Screenings across Toronto and the GTA

We Deliver Gravel serves homeowners and contractors right across Toronto, Vaughan, and the entire GTA, from Scarborough and Etobicoke to Willowdale, Don Mills, High Park, and Leslieville. In Vaughan, we cover Woodbridge, Maple, Kleinburg, Thornhill, Concord, and the surrounding areas. We know GTA soil and exactly what Ontario winters do to a poorly drained patio base, and that knowledge comes with every order we send out.

We also carry everything your patio project needs in one place. From HPB and Limestone Screenings for your bedding layer to Granular A and 3/4 Clear Limestone for the base beneath, plus Concrete Sand for interlock joints and Pea Gravel or River Rock for decorative finishes, you can order it all online and schedule delivery at a time that suits your build.

Get your patio base delivered, book gravel delivery in Toronto and Vaughan today

Whether you are laying a new patio, rebuilding a walkway, or just topping up the bedding under a few loose stones, We Deliver Gravel makes it simple to get the right material to your door without the guesswork. You can order online and schedule your delivery at a time that works for your project, and if you are still weighing up HPB against Limestone Screenings, call us at 647-868-2447. Our team will help you figure out which one suits your soil, how much to order, and when we can get gravel delivery in Toronto and Vaughan out to your site.